1. Field of the Invention
This disclosure relates to the field of elevating lift apparatus. In particular, to elevating lift apparatus mounted on vehicles for the lifting of loads such as sensor suites.
2. Description of the Related Art
In military strategy, there is a great desire to be able to view the enemy and bring firepower to bear on enemy soldiers, while still keeping your soldiers out of harm""s way. One method which is used to bring such firepower upon an enemy from a distance is the artillery barrage. Artillery weapons are generally designed to be able to deliver ordnance onto a target from a great distance and thus are capable of firing indirectly at targets which they cannot see because of intervening terrain by firing their ordnance in high arcs. As will be understood by those of skill in the art, artillery batteries are often safe from enemy fire, as the enemy generally cannot locate them to direct retaliatory fire, and even if the enemy might determine their location, the enemy may not have access to weapons with sufficient range to deliver its ordnance onto the artillery battery.
The problem with firing artillery, however, is that the ordnance fired must be aimed so that it is accurately delivered onto enemy positions, instead of just being fired randomly, or worse upon friendly positions which may be nearby. Since the artillery batteries are out of sight of the enemy, it is not possible for the artillery gunners to sight their weapons directly. Artillery has traditionally relied on forward observers to identify targets, provide the enemy positions, and track where the ordnance is hitting and adjust the fire appropriately.
In many instances, forward observers have been infantry and armor soldiers, or field artillery soldiers, that had worked their way to positions within sight of the enemy whether ahead of the front lines or at the front lines. They then instructed (by radio or some other remote communications method) the fire control center, of artillery units, on adjustment of fire by methods familiar to those of ordinary skill in the art in order to hit targets. As visual enhancement technologies have gotten more sophisticated, the individual has had an increased range and ability to see targets. These technologies have included a simple pair of binoculars, advanced night vision and RADAR systems, and other sensing apparatus. As the technology has developed, so generally has its bulk and weight. It is also desirable to put the forward observers in a vehicle to better protect him/her from the enemy""s likely retaliation of the barrage. Therefore, in much of artillery forward observing activity, a vehicle carrying a sensor suite of various different types of sighting apparatus is regularly used for forward sighting with a crew of a few individuals locating targets and returning those locations to the batteries.
As will be understood, the vehicle used is much larger than a soldier performing such duties. Thus, the vehicle needs to use various specialized tactics to avoid detection and retaliatory fire. One of these tactics is to position the vehicle behind some type of concealment and then raise the sensor suite above the cover. In this instance, the sensor suite could be damaged by retaliatory fire, but the vehicle (and its human occupants) may be protected by the vehicle""s armor and the cover behind which they are concealed. A still further tactic is to position the vehicle in defilade, which is placing the vehicle on one side of a hill (using the bulk of the hill to protect the vehicle) and raising the sensor suite above the vehicle in a manner so that the sensor suite can see over the hill and down the other side. Defilade relies on the use of mathematical relationships and available angles to provide the sensor suite with a clear field of view. In particular, the sensor suite needs to have a clear sight line downward in front of the vehicle to observe down the far side of the hill, without the vehicle""s body blocking that view and with the vehicle still hidden by the hill from the enemy in front of it.
Further, because of the sensitivity of the sensor suite and the accuracy required to effectively assist artillery batteries in bringing ordnance onto desired targets, the mount for the sensor suite on the vehicle needs to be designed to reduce vibration and unintended motion of the suite to increase the accuracy of the targeting. This is particularly true when the suite is being operated at an extreme range from desired targets. Anticipated motion and motion of relatively small magnitudes is generally compensated for through the use of an isolating or gimble mount for the sensor suite. While the isolating mount is successful at dealing with motion whose direction and intensity is known, it cannot always compensate for motion which is unexpected or of particularly large magnitude or which occurs in a manner that bypasses the isolating mount""s systems. It is also easier to compensate for motion in certain directions (such as linear motion) with an isolating mount whereas other types of motion (such as rotational) are more difficult to deal with. For this reason, it is therefore desirable to minimize any unintended motion and to dampen any potentially large motions. This is generally accomplished by keeping the sensor suite as stable as possible by providing the sensor suite an attachment to the vehicle which is as stable as possible and/or trying to eliminate motion of the vehicle which could be unintentionally transmitted to the suite.
In order to employ effective artillery tactics, it is necessary to mount the sensor suite at a high point on the vehicle so that it can have the field of view necessary for use in defilade positions or, ideally, to mount the sensor suite on a boom or platform which can be raised above the vehicle for this use. Such mountings keep the vehicle used by a forward observer from narrowing the sensor suite""s field of view and allow the vehicle to be positioned out of sight. Previously, there were two methods of mounting the sensor suite to the vehicle. In one method, which was generally used for lighter vehicles, the sensor suite was mounted to the roof of the vehicle which was carrying it. This provided for a fairly rigid, stable platform for the device but also created certain problems. For one, the sensor suite would often take up the position of the defensive weapon mounted on the vehicle, leaving the occupants of the vehicle more vulnerable to attack. Further, the height of the suite was limited to that of the vehicle to which it was attached and thus could lead to parts of the vehicles body being vulnerable when the suite was in use. The vehicle may also have blocked a portion of the sensor suite""s view if the vehicle was to be in a good defilade position.
Still further problems resulted from the vulnerability of the sensor suite when mounted on the roof. The suite could be hit by branches or other objects which could damage the sensor suite as the vehicle traveled to its forward observer location. The sensor suite is, by design, to be above the protective body of the vehicle. A more specialized problem, but also a significant one, is that the vehicle with the sensor suite mounted on its roof generally does not fit into standardized transports. This is particularly problematic in air transport scenarios. The C-130 aircraft, which is regularly used by the United States to transport vehicles to battle zones, is designed for extremely efficient storage of vehicles. Military vehicles are built to fairly standardized sizes (essentially blocks) allowing large numbers of them to be placed in close proximity to each other, within the storage areas in a C-130. For this reason, items attached to the exterior surfaces of the vehicles are often removed to allow the vehicles to be more closely packed. This can include defensive weaponry and the sensor suite discussed above. The difficulty with this situation is that the sensor suite is an instrument which must be xe2x80x9cbore sightedxe2x80x9d before it is accurate. Whenever it is removed and replaced it must be re-sighted due to possible inconsistencies with its new placement upon its repositioning on the vehicle. This is a time-consuming and undesirable outcome under combat conditions, so it is preferred that the sensor suite be mounted on the vehicle in a manner such that the vehicle can be packed for transport, without having to remove the sensor suite. It is particularly valuable if the vehicle can be packed for C-130 air transport.
In order to avoid some of the problems with the rigid roof mounting of the sensor suite, extensible booms have been used to attach the sensor suite to the vehicle. These are generally of the form of a single tube or cylinder which extend straight upward from vehicle carrying the sensor suite on a platform at the top. This type of structure is referred to as a mast, and allows for very efficient raising of the senor suite above the roof of the vehicle eliminating many of the problems of the roof mount. It also allows for a large amount of height to be gained without the need for a lot of machinery or lift mechanism. The use of a mast also helps isolate the sensor suite from the vehicle to help keep the vehicle more out of harm""s way when the sensor suite is in use.
While a variety of lifts may be used to raise the sensor suite from the vehicle, the mast is particularly desirable because it provides two additional features not present in most other types of lifts. In particular, the platform at the pinnacle of the mast is always kept parallel as the mast raises vertically, meaning that the sensor suite can be operated with the mast at any elevation. The mast is also simple, inexpensive, and collapses into a small space. The mast itself, however, still has many problems because it is not a particularly stable structure, especially when extended to maximum height.
In the first instance, the extended mast is very top heavy. Because it is a single (generally hollow) cylinder, the mast is generally quite light weight, while the sensor suite, which is at the top of the mast, is relatively heavy. This means that when the mast is extended, the center of gravity of the vehicle moves up the mast. This can result in multiple problems. If the vehicle is light, or has extensive suspension, the vehicle may rock or sway when the mast is extended as the mass of the vehicle is insufficient to compensate for the remote mass of the sensor suite. This may lead to problems with the delicate sensors being unable to be used at their maximum ranges. This is why masts generally have only been used on heavier vehicles as the vehicles provide more support and help keep the center of gravity of the vehicle mast system closer to the ground. However, the use of heavier vehicles is not as desirable as it makes the vehicle dramatically more expensive, can slow the vehicle down making it harder to evade the enemy, and can also make it more easily detected.
Another problem presented by the mast is the vulnerability of the mast itself. As stated above, the mast is generally light and hollow. This provides for a strong resistance to forces imposed longwise on the cylinder (e.g. the sensor suite""s mass pushing back toward the earth) but is very vulnerable to forces pushing against the sides of the cylinder as is known to those of ordinary skill in the art. A small amount of force in the plane of the vehicle can result in a large torsional force being asserted by the sensor suite (and/or the vehicle) on the structure of the mast. The mast therefore should not be exposed to significant forces in the plane of the vehicle when the mast is extended. These can include wind or acceleration of the vehicle as these forces may lead to bending of the mast. The latter is particularly problematic because it means that the vehicle needs to remain stationary when the sensor suite is deployed regardless of height, which can make it more vulnerable to observation. Further, when the mast is extended, the vehicle cannot move, even at slow speeds, as any acceleration will be magnified by the mass of the sensor suite and can generate a torsional force on the mast in an undesirable direction leading to damage to the mast and possible collapse and failure of the sensor suite.
Because of these and other previously unknown problems in the art, it is therefore desirable to have a elevating lift for raising and lowering a load (such as a sensor suite) onboard a vehicle which allows for the transport of such a fitted vehicle in a standard transport without removal of the sensor suite from the vehicle, and which provides for a more stable support for a load than is available from a traditional mast. It is further desired that the load of the elevating lift be maintained in parallel at all positions.
In an embodiment, disclosed herein is a vehicle including an elevating lift comprising: a vehicle, the vehicle having a plane in which it travels; a load table upon which a load to be lifted is placed; a support, attached to the vehicle; at least two arms, each of said arms pivotally attached at a first end to the load table and pivotally attached at an opposing end to the support at a point spaced vertically above where the support is attached to the vehicle; a linear actuator positioned such that when the linear actuator changes length, the arms are forced to rotate at the opposing ends in an arc relative to the support, the arms being parallel to each other as the arms traverse the arc; and a motion translator operatively connected to the load table such that as the arms rotate, the load table also rotates in a manner such that the load table is in a generally parallel plane to the plane of the vehicle at all positions of the arms.
In an embodiment, the arms may be attached on opposing edges of said load table, the motion translator may comprise rods and cranks, the linear actuator may change length through screw motion and/or may be a piston operated using at least one of hydraulics and pneumatics, and/or the load table may be able to be raised higher than the highest point of said vehicle.
In an embodiment, the vehicle may comprise a military vehicle such as, but not limited to, an M1025 small tactical vehicle and/or the load may comprise a sensor suite having a field of view which may be unimpaired by the vehicle when the load table is at a predetermined point.
In yet another embodiment, the vehicle may further include a swing arm which can be moved between an engaged and an unengaged position which in turn may be rigidly attached to the load table.
In yet another embodiment, described herein is a vehicle including an elevating lift comprising: a vehicle having a bed and a cab; a load table upon which a load to be lifted is placed; a support, attached in the bed of the vehicle; at least two arms, each of the arms pivotally attached at a first end to the load table and pivotally attached at an opposing end to the support; a linear actuator positioned such that when the linear actuator changes length, the arms are forced to rotate at the opposing ends in an arc relative to the support, the arms being parallel to each other as the arms traverse the arc; and a motion translator operatively connected to the load table such that as the arms rotate, the load table also rotates in a manner such that the load table is in a generally parallel plane to the plane of the vehicle at all positions of the arms; wherein the load table can be moved from a lowered position wherein the load is generally within the bed of the vehicle, to an intermediate position wherein the load is above the highest point of the cab, and a higher point above the intermediate point.
In a still further embodiment, the vehicle may further include a swing arm which rigidly engages the load table when the load table is in the intermediate position.